1. Field of the Invention
The invention concerns electromagnetic switching apparatus, particularly a motor contactor, with auxiliary contacts, with a contact bridge carrier and contact bridges held in the contact bridge carrier in tiers, one behind the other, as seen in the switching direction, the latter contact bridges being able to be brought into contact with fixed contact members which are attached to a housing part, and which are flanked by walls of the housing part which form at least in part the arcing chambers for the contact points and extend into slots of the contact bridge carrier forming labyrinths.
2. Description of the Prior Art
In one known motor contactor (German Auslegeschrift 1,024,151), the three main switch poles are disposed facing the attachment plane of the switching apparatus, and the actuating mechanism is disposed above the contact arrangement for the main switch poles, as seen from the attachment plane. Between the actuating mechanism and the main switch poles are situated small auxiliary switch blocks which are placed in the housing as a separate switching unit.
In another known electromagnetic switching apparatus design (German Auslegeschrift 1,237,668), four auxiliary switch poles are installed in the tier adjacent to the drive and, in a further auxiliary switch tier placed on top thereof, another four auxiliary switch poles are installed. The walls between the individual switch poles, which form the arcing chambers, are inserted into slots, and the contact bridge carrier likewise takes in the wall ends by means of slots. In this apparatus, electrically separating the individual auxiliary switch poles, which switch poles are disposed on top of each other, is possible only if the potential difference is small, as the contact bridges lie here in a window opening of the contact bridge carrier and there are no partitions between the fixed contact members. If such switching apparatus were used for a motor contactor, only three auxiliary switch poles associated with the main switch poles could be put on, if the width of the contactor is determined according to the main switch poles.
It is therefore an object of the present invention to create an electromagnetic switching apparatus of the kind mentioned above and, particularly, a motor contactor with auxiliary contacts, which ensures good potential separation of the individual switch poles from each other and which, at the same time, is of simple design.